Worm gear

For our next model, we will build a gearbox that contains a worm gear. Every time the worm gear makes one complete rotation, the spur or straight gear meshed to it will progress by one tooth. We are using a 24-tooth spur gear in this model. Notice how this spur gear does not have any bevels. You will find that our spur gear will rotate very slowly, but we have a mechanical advantage of 24! Speed is not always the goal of a gearbox. Besides greater torque, one feature I like about using a worm gear is the greater amount of control. If you are building an arm where great precision is required, the worm gear will allow you to align your output appendage with a high degree of accuracy. The EV3 shaft encoders can guide the motors themselves to within one degree of accuracy. So with this combination of gears, we have an accuracy of 1/24 of a degree.

In the following seven steps, we will build the gearbox with a worm gear:

We can download a similar program to what you wrote for the beveled gear. Increase the number of rotations, as this gearbox will move slowly. Again, make sure that your motor is plugged into port A of your EV3 brick.

When you executed the preceding program, you saw how slowly the straight gear turned. It can be difficult to visualize how many times the worm gear has turned. We are now going to write a more complicated program that will allow us to display the number of rotations of the worm gear on the EV3 brick display.